By means of this known apparatus, so called brush plating may be carried out, which is an electrolytic method for metallizing without need of immersing the workpiece in an electrolytic bath. In each treatment step, one or more electrodes, normally anodes, which typically are made of graphite and wound with an absorbing material, such as cotton or polypropylene wool or the like, are located adjacent the rotating workpiece, the absorbing material being in contact with the workpiece while the electrode proper may be located at a distance of e.g. 0.5 mms or less from the workpiece. The electrolyte is supplied to the area of the electrode and the workpiece and metals ions are deposited from the electrolyte on the surface of the workpiece adjacent to the electrode. In order to obtain a complete plating treatment, several steps are required. A first step may be degreasing, a second activation or pickling, a third deposition of a binding metal layer and a fourth deposition of the main metal layer. Each of said steps is carried out with a specific electrolyte and one or more specific electrodes.
Although it is possible with said apparatus to obtain high quality plating, there are nevertheless disadvantages as to the efficiency thereof. In practice, an electrode holder is provided to which a first electrode must be mounted for carrying out the first treatment step, i.e. degreasing. In addition, a hose or the like must be applied to the electrode to supply the degreasing electrolyte to the electrode. When the degreasing step is terminated, the electrode must be released from the holder and another electrode, e.g. an electrode for a pickling electrolyte, be mounted on the holder and in addition, another electrolyte container must be taken to the vicinity of the holder and connected to the pickling electrode by a hose. In an analogous manner, the treatment proceeds until the plating is completed by deposition of the main metal layer. In practice, such a plating operation may comprise four or more treatment steps and it is evident that the treatment as a whole is very laborious.